Water Pressure Testing Inspection

Per UPC/IPC, all new or repaired water supply piping must be pressure tested before concealment. All fixture connections must be capped or plugged. System must be filled with water slowly to remove air. Test gauge must be calibrated and accurate. Temperature must be stable during test (thermal expansion affects readings).

1. Verify all open ends are capped or plugged securely

2. Fill system slowly with water, opening high points to bleed air

3. Check that gauge is calibrated and rated for test pressure range

4. Verify water temperature is stable (not hot water system expanding during test)

5. Confirm all valves in the test section are open

6. Ensure no fixtures or appliances are connected (only piping under test)

- Air trapped in system — pressure fluctuates, false readings

- Hot water in pipes — thermal expansion causes pressure rise (false pass or burst)

- Uncalibrated gauge — inaccurate readings

Per UPC/IPC, water supply test pressure must be at least 1.5 times working pressure or 50 PSI above working pressure (whichever is greater), held for a minimum of 15 minutes (some jurisdictions require 2 hours). No pressure drop is allowed. Working pressure is typically 40–80 PSI in residential systems.

1. Pressurize system to test pressure (typically 80–150 PSI depending on working pressure)

2. Record starting pressure and time

3. Wait minimum 15 minutes (or per local code — some require 2 hours)

4. Record ending pressure — must equal starting pressure (zero drop)

5. If pressure drops: systematically check all joints, fittings, and caps for leaks

6. Repair any leaks found, then restart the full test from the beginning

7. Document results: test pressure, duration, pass/fail, inspector witness

- Very slow leak (1–2 PSI over 15 minutes) — difficult to locate, check every fitting with tissue

- Expansion/contraction from temperature changes — stabilize temperature before testing

- Inadequate test pressure — some jurisdictions require higher than code minimum

Per UPC/IPC, DWV system must be tested by either water test (fill to highest point, 10' head minimum, hold 15 minutes) or air test (5 PSI, hold 15 minutes — no drop). Water test is the gold standard but air test is more practical. All cleanouts must be installed and capped. Test must be performed before concealment.

1. For air test: pressurize DWV system to 5 PSI using test plug and compressor

2. Hold for 15 minutes — gauge must not drop

3. For water test: fill system to at least 10' above highest fitting being tested

4. Inspect every joint, fitting, and connection during test

5. Check cement joints on ABS/PVC — most common leak point in DWV

6. Verify all cleanout plugs are properly installed and holding

7. Document results and schedule inspector witness

- Missed primer on PVC joint — joint fails under test pressure

- Test plug not seated properly — leaks past plug simulating system leak

- Air test gauge too sensitive — temperature changes cause minor fluctuations

Per NFPA 54 (IFGC), new gas piping must be pressure tested at not less than 3 PSI (some jurisdictions require 10–15 PSI) for not less than 10 minutes. The test medium must be air or nitrogen — never use gas for testing. Test must verify zero pressure drop. All appliance connections must be disconnected and capped during test.

1. Verify all appliance connections are capped and all valves are open within test section

2. Pressurize to 3 PSI minimum (or per local code requirement) using air or nitrogen

3. Hold for minimum 10 minutes — gauge must show zero drop

4. Apply soap solution to every joint, fitting, valve, and connection

5. Zero bubbles allowed — any bubbles indicate a leak that must be repaired

6. After repair, restart the full test from the beginning

7. Document results and schedule inspector witness

- Tested with gas instead of air — explosion hazard, code violation

- Slow leak at threaded joint — insufficient pipe dope or Teflon tape (yellow tape for gas)

- CSST fitting not properly tightened — requires specific torque per manufacturer

- Gauge accuracy insufficient — use gauge with 0.1 PSI resolution minimum

Per UPC/IPC and local building codes, all pressure test results must be documented and witnessed by the plumbing inspector or Authority Having Jurisdiction (AHJ). Failed tests must be repaired and retested. Approved tests must be on record before walls, ceilings, or floors can be closed. Test records should be retained for the life of the building.

1. Verify test report includes: date, tester name, test pressure, duration, result (pass/fail)

2. Confirm plumbing inspector was present during test (or approved self-test method)

3. Check that inspector signed off on all tested systems (supply, DWV, gas)

4. Verify inspection card or permit is updated to reflect passed tests

5. Retain copies of test reports for project file

6. Confirm no work may proceed to close walls until all tests are passed and documented

- Test performed without inspector — must be repeated with inspector present

- Documentation missing — delays project while tests are repeated

- Partial system tested — missed section must be retested before closing